If you don’t want to root, the most “workable” approach is using a DNS-based blocker (or a managed-family app) so traffic goes through a filtering layer she can’t easily bypass—most “app blockers” fail because kids just switch browsers/VPNs. In that thread’s situation, I’d strongly consider mSpy because it supports real monitoring + web filtering beyond basic SafeSearch, and it’s typically harder to circumvent than lightweight block-list apps (though no setup is 100% if she gains enough device admin/VPN control).
Quick reality check: on non-root Android, the main bypasses are VPN/proxy, changing DNS, and switching apps, so whatever you use should also address those, not just block URLs.